/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.utils.reflect;

import java.lang.reflect.GenericArrayType;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

/** Provides information about, and access to, a single field of a class or interface.
 * @author nexsoftware */
public final class Field {

    private final java.lang.reflect.Field field;

    Field (java.lang.reflect.Field field) {
        this.field = field;
    }

    /** Returns the name of the field. */
    public String getName () {
        return field.getName();
    }

    /** Returns a Class object that identifies the declared type for the field. */
    public Class getType () {
        return field.getType();
    }

    /** Returns the Class object representing the class or interface that declares the field. */
    public Class getDeclaringClass () {
        return field.getDeclaringClass();
    }

    public boolean isAccessible () {
        return field.isAccessible();
    }

    public void setAccessible (boolean accessible) {
        field.setAccessible(accessible);
    }

    /** Return true if the field does not include any of the {@code private}, {@code protected}, or {@code public} modifiers. */
    public boolean isDefaultAccess () {
        return !isPrivate() && !isProtected() && !isPublic();
    }

    /** Return true if the field includes the {@code final} modifier. */
    public boolean isFinal () {
        return Modifier.isFinal(field.getModifiers());
    }

    /** Return true if the field includes the {@code private} modifier. */
    public boolean isPrivate () {
        return Modifier.isPrivate(field.getModifiers());
    }

    /** Return true if the field includes the {@code protected} modifier. */
    public boolean isProtected () {
        return Modifier.isProtected(field.getModifiers());
    }

    /** Return true if the field includes the {@code public} modifier. */
    public boolean isPublic () {
        return Modifier.isPublic(field.getModifiers());
    }

    /** Return true if the field includes the {@code static} modifier. */
    public boolean isStatic () {
        return Modifier.isStatic(field.getModifiers());
    }

    /** Return true if the field includes the {@code transient} modifier. */
    public boolean isTransient () {
        return Modifier.isTransient(field.getModifiers());
    }

    /** Return true if the field includes the {@code volatile} modifier. */
    public boolean isVolatile () {
        return Modifier.isVolatile(field.getModifiers());
    }

    /** Return true if the field is a synthetic field. */
    public boolean isSynthetic () {
        return field.isSynthetic();
    }

    /** If the type of the field is parameterized, returns the Class object representing the parameter type at the specified index,
     * null otherwise. */
    public Class getElementType (int index) {
        Type genericType = field.getGenericType();
        if (genericType instanceof ParameterizedType) {
            Type[] actualTypes = ((ParameterizedType)genericType).getActualTypeArguments();
            if (actualTypes.length - 1 >= index) {
                Type actualType = actualTypes[index];
                if (actualType instanceof Class)
                    return (Class)actualType;
                else if (actualType instanceof ParameterizedType)
                    return (Class)((ParameterizedType)actualType).getRawType();
                else if (actualType instanceof GenericArrayType) {
                    Type componentType = ((GenericArrayType)actualType).getGenericComponentType();
                    if (componentType instanceof Class) return ArrayReflection.newInstance((Class)componentType, 0).getClass();
                }
            }
        }
        return null;
    }

    /** Returns true if the field includes an annotation of the provided class type. */
    public boolean isAnnotationPresent (Class<? extends java.lang.annotation.Annotation> annotationType) {
        return field.isAnnotationPresent(annotationType);
    }

    /** Returns an array of {@link Annotation} objects reflecting all annotations declared by this field,
     * or an empty array if there are none. Does not include inherited annotations. */
    public Annotation[] getDeclaredAnnotations () {
        java.lang.annotation.Annotation[] annotations = field.getDeclaredAnnotations();
        Annotation[] result = new Annotation[annotations.length];
        for (int i = 0; i < annotations.length; i++) {
            result[i] = new Annotation(annotations[i]);
        }
        return result;
    }

    /** Returns an {@link Annotation} object reflecting the annotation provided, or null of this field doesn't
     * have such an annotation. This is a convenience function if the caller knows already which annotation
     * type he's looking for. */
    public Annotation getDeclaredAnnotation (Class<? extends java.lang.annotation.Annotation> annotationType) {
        java.lang.annotation.Annotation[] annotations = field.getDeclaredAnnotations();
        if (annotations == null) {
            return null;
        }
        for (java.lang.annotation.Annotation annotation : annotations) {
            if (annotation.annotationType().equals(annotationType)) {
                return new Annotation(annotation);
            }
        }
        return null;
    }

    /** Returns the value of the field on the supplied object. */
    public Object get (Object obj) throws ReflectionException {
        try {
            return field.get(obj);
        } catch (IllegalArgumentException e) {
            throw new ReflectionException("Object is not an instance of " + getDeclaringClass(), e);
        } catch (IllegalAccessException e) {
            throw new ReflectionException("Illegal access to field: " + getName(), e);
        }
    }

    /** Sets the value of the field on the supplied object. */
    public void set (Object obj, Object value) throws ReflectionException {
        try {
            field.set(obj, value);
        } catch (IllegalArgumentException e) {
            throw new ReflectionException("Argument not valid for field: " + getName(), e);
        } catch (IllegalAccessException e) {
            throw new ReflectionException("Illegal access to field: " + getName(), e);
        }
    }

}